JP2009068214A - Superstructure of bridge, method of constructing superstructure of bridge, and method of increasing width of superstructure of bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superstructure of a bridge in which the arrangement of girder parts around receiving members is hard to be complicated. <P>SOLUTION: This superstructure A of a bridge comprises the girder parts 11, extension floor boards 13, 20 extending from the girder parts 11 sideways, the receiving members 30 secured to the lower parts of the girder parts 11, respectively, and struts 40 diagonally rising from the receiving members 30. The extension floor boards 13, 20 are supported by the struts 40. An engagement projection is formed on the rear surface of the receiving member 30. An engagement recess is formed in the lower outer surface of the girder part 11 at a depth equal to or smaller than the covering depth of reinforcements. With the engagement projection engaged with the engagement recess, the receiving member 30 is secured to the girder part 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bridge superstructure, a bridge superstructure construction method, and a bridge superstructure widening method.

Patent Document 1 discloses a bridge upper structure (a so-called box girder with a strut) of a type in which an overhanging slab that projects from the main girder portion to the side is supported by a strut that rises obliquely upward from the lower portion of the main girder portion. , 2 and the like. In addition, in the bridge upper structure currently disclosed by patent documents 1, 2, the structure which connects the lower end part of a strut to the receiving member embed | buried under the main girder part (core segment) integrally beforehand beforehand. Adopted.
JP 2001-164512 A JP 2001-164513 A

  In the bridge superstructures of Patent Literatures 1 and 2, since the entire receiving member is embedded in the core segment, there is a possibility that the bar segment arrangement around the receiving member may be complicated. In addition, in order to respond to demands for widening and reinforcing the bridge superstructure, struts may be installed later at positions that were not assumed when the core segment was manufactured. In the bridge superstructures of Patent Documents 1 and 2 that are buried, struts cannot be installed later at positions that were not assumed. It is also possible to embed the receiving member after the core segment is manufactured, but in this case, a large recess that allows the entire receiving member to enter while avoiding the reinforcing bars arranged in the core segment is formed by chipping. Since it needs to be formed, there is a risk that the construction period and construction cost will increase.

  From this point of view, the present invention is a bridge upper structure of a type in which an overhanging slab extending from the main girder portion to the side is supported by struts, and the reinforcement of the main girder portion around the receiving member The first task is to provide a bridge superstructure that is difficult to be complicated, and to provide a method for constructing a bridge superstructure that can easily respond to requests for widening and reinforcing the bridge superstructure. As a second problem, a third problem is to provide a method for widening a bridge superstructure that can easily and quickly widen an existing bridge superstructure including a main girder portion in which a receiving member is not embedded. To do.

  The bridge superstructure according to the present invention that solves the first problem is fixed to a main girder part, an overhanging slab that projects from the main girder part to the side, and a lower part of the main girder part. A bridge upper structure in which the overhanging slab is supported by the struts, and an engaging projection is formed on the back surface of the receiving member. An engagement recess having a depth equal to or less than the cover thickness of the reinforcing bar is formed on the outer surface of the lower portion of the main girder, and the engagement projection is inserted into the engagement recess. In this state, the receiving member is fixed to the main beam part.

  In the present invention, since the depth of the engaging recess formed in the main girder is set to be equal to or less than the cover thickness of the reinforcing bar, the receiving member is attached to the surface layer of the main girder. In this case, unlike the case where the entire receiving member is embedded in the main girder part, it is not necessary to consider the connection with the receiving member when reinforcing bars are placed below the main girder part. The bar arrangement in the lower part of the is simplified. In the bridge superstructure according to the present invention, the shearing force acting on the receiving member is transmitted to the main girder portion by meshing the engaging convex portion provided on the receiving member with the engaging concave portion provided on the main girder portion. Will be.

  Further, in the present invention, the depth of the engagement recess formed in the main girder portion is set to be equal to or less than the cover thickness of the reinforcing bar, so when the engagement recess is formed after the main girder portion is manufactured or installed. In the case where the engaging recess is formed at the time of manufacturing the main girder portion, a large-scale chipping operation or the like is not necessary, and the processing or the like applied to the mold is light.

  In the present invention, it is desirable that a protrusion having a frame shape is the engaging protrusion, and a groove having a frame shape is the engaging recess. In this case, the chipping work and the like, and the processing applied to the formwork become much lighter.

  The material of the receiving member is not particularly limited, but is preferably made of ultra high strength fiber reinforced concrete. If the receiving member is made of ultra-high-strength fiber reinforced concrete, reinforcing members such as reinforcing bars are not required, so the receiving member can be made thinner, and in addition, there is no risk of corrosion. Easy maintenance.

  The back surface of the receiving member may be roughened, and the back surface of the receiving member may be bonded to the main beam portion with an adhesive. In this way, the receiving member is not only firmly fixed to the main girder part, but also rainwater or the like is difficult to enter between the back surface of the receiving member and the outer surface of the main girder part. It becomes difficult to do.

  The construction method of the bridge superstructure according to the present invention that solves the second problem described above is that the overhanging slab that projects from the main girder portion to the side is inclined from the receiving member fixed to the main girder portion. A method of constructing a bridge upper structure of a type supported by struts rising upward, and after forming an engagement recess having a depth less than the cover thickness of the reinforcing bar on the outer surface of the lower part of the main girder part The receiving member is fixed to the main girder in a state where the engaging convex portion formed on the back surface of the receiving member enters the engaging concave portion, and then the lower end portion of the strut is connected to the receiving member. The upper end of the strut is connected to the overhanging slab.

  The bridge superstructure construction method according to the present invention is basically characterized in that a receiving member interposed between the lower end portion of the strut and the main girder portion is retrofitted. If the receiving member is retrofitted, its mounting position and shape can be set relatively freely. Therefore, there is a request for widening or reinforcing the bridge superstructure after the main girder is manufactured or installed. Even if it is, it becomes possible to cope easily. In addition, since the depth of the engagement recess formed on the outer surface of the main girder is set to be less than the cover thickness of the reinforcing bar, a large scale is required when the engagement recess is formed after the main girder is manufactured or installed. When the main recess portion is formed with an engaging recess, the processing applied to the mold is light. In the bridge superstructure constructed according to the present invention, the shear force acting on the receiving member is caused by the engagement of the engaging convex portion provided on the receiving member and the engaging concave portion provided on the main girder portion. Will be transmitted to.

  The method for widening the bridge superstructure according to the present invention that solves the third problem described above is provided with an overhanging slab for widening on the side of an existing floor slab, and fixed to a main girder part that supports the existing floor slab. A method of widening an existing bridge upper structure by supporting the overhanging slab on a strut that rises obliquely upward from a receiving member formed on the outer surface of the lower part of the main girder, A recess forming step for forming an engagement recess having a depth equal to or less than a thickness; and the engagement member formed on the back surface of the reception member is inserted into the engagement recess, and the receiving member is moved to the main beam portion. A receiving member installation step for fixing to the receiving member, a strut installation step for connecting the lower end portion of the strut to the receiving member and raising the strut obliquely upward from the receiving member, and a base end portion of the overhanging slab To the existing floor slab and the overhang Characterized in that it comprises a connecting step of connecting the upper end of the strut to the distal end of the plate, the.

  In short, the method for widening the bridge superstructure according to the present invention attaches the receiving member interposed between the lower end portion of the strut and the main girder portion, and connects the lower end portion of the strut to the attached receiving member. There is a feature. If it does in this way, even if it is a case where the receiving member is not embed | buried under the main girder part, it will become possible to expand the existing bridge superstructure simply and rapidly. In addition, since the depth of the engagement recess formed on the outer surface of the main girder is set to be less than the cover thickness of the reinforcing bar, a large scale is required when the engagement recess is formed after the main girder is manufactured or installed. When the main recess portion is formed with an engaging recess, the processing applied to the mold is light. In addition, when forming an engagement recessed part at the time of manufacture of a main beam part, the manufacturing process of a main beam part becomes a recessed part formation process. By the way, in the bridge upper structure widened by the present invention, the shearing force acting on the receiving member is caused by the engagement of the engaging convex portion provided on the receiving member and the engaging concave portion provided on the main girder portion. Will be transmitted to.

According to the bridge superstructure according to the present invention, the reinforcement of the main girder around the receiving member is difficult to be complicated.
According to the method for constructing a bridge superstructure according to the present invention, it is possible to easily respond to requests for widening and reinforcing the bridge superstructure.
According to the method for widening a bridge superstructure according to the present invention, it is possible to easily and quickly widen an existing bridge superstructure including a main girder portion in which a receiving member is not embedded.

  As shown in FIG. 1A, the bridge upper structure A according to the present embodiment has a core structure 10 including a main girder portion 11 and an overhanging slab 13 and a side from the overhanging slab 13 to the side. The widened floor slab 20 for widening, a receiving member 30 fixed to the lower part of the main girder 11, and a strut 40 that rises obliquely upward from the receiving member 30 are configured. That is, the bridge superstructure A includes a main girder portion 11, overhanging slabs 13 and 20 projecting sideways from the main girder portion 11, and a receiving member 30 fixed to the lower portion of the main girder portion 11. The strut 40 rises obliquely upward from the receiving member 30.

  In addition, in this embodiment, it is possible to add a widened extended floor slab 20, a receiving member 30, and a strut 40 to the core structure 10 that is an existing bridge upper structure installed between bridge piers (not shown) by retrofitting. The bridge superstructure A to be formed is illustrated. Incidentally, a new bridge upper structure formed by attaching the receiving member 30 and the strut 40 when the core structure 10 is installed between the bridges is also included in the bridge upper structure of the present invention.

  The core structure 10 is a so-called box girder, a pair of left and right main girder parts (webs) 11, 11, a central floor slab 12 provided between the upper ends of the main girder parts 11, 11, and a main girder part. 11, 11 and 11 and 11 and 11 and 11 and 11 and 11 and 11, and the bottom slab 14 provided between the lower ends of the main girder portions 11, 11 is provided. The core structure 10 is made of concrete, and reinforcing members such as reinforcing bars are arranged therein. The core structure 10 may be constructed by cast-in-place concrete, but a plurality of precast segments divided in the bridge axis direction are connected in series, and a tensile force is applied to the PC steel material arranged along the bridge axis direction. It can also be constructed by connecting multiple precast segments.

  The main girder portion 11 has a plate shape, and is integrally connected to the central floor slab 12 and the overhanging floor slab 13 at the upper end portion thereof, and is integrally connected to the bottom plate 14 at the lower end portion thereof. As shown in FIG. 1B, a pedestal portion 15 that serves as a mounting seat for the receiving member 30 is provided on the outer surface (side surface on the extended floor slab 20 side) of the lower portion of the main girder portion 11.

  In the present embodiment, the pedestal portion 15 has a triangular cross section, and includes a mounting surface 15 a having the normal direction of the axial direction of the strut 40. The pedestal portion 15 is a portion formed integrally with the other portion of the main girder portion 11 when the core structure 10 (core segment) is manufactured. In the present embodiment, the pedestal portion 15 extends in the bridge axis direction (the direction perpendicular to the paper surface). It is formed continuously.

  As shown in FIG. 2A, an engagement recess 151 is formed on the mounting surface 15 a of the pedestal 15. The depth of the engagement recess 151 is set to be equal to or less than the cover thickness of the reinforcing bar in the pedestal portion 15. That is, the depth of the engaging recess 151 is set to a size that does not expose a reinforcing bar (not shown) that is arranged in the surface layer portion of the pedestal 15 so as not to be exposed. Yes. Although there is no restriction | limiting in particular in the form of the engagement recessed part 151, In this embodiment, it consists of a groove | channel which exhibits a frame shape. In this embodiment, the groove having a rectangular frame shape is the engaging recess 151, but the present invention is not limited to this, and the groove having a circular frame shape may be the engaging recess 151. Moreover, in this embodiment, although the engagement recessed part 151 is formed by the continuous groove | channel which does not have a cut | interruption, you may form the engagement recessed part 151 by the groove | channel formed intermittently.

  Further, anchor insertion holes 152, 152,... And anchor bar insertion holes 153 are formed in the pedestal portion 15. The anchor insertion hole 152 and the anchor bar insertion hole 153 are formed avoiding a reinforcing bar (not shown) arranged in the pedestal portion 15. The anchor insertion hole 152 is formed around the engagement recess 151, and has a hole diameter slightly larger than the shaft diameter of the anchor bolt 33. The anchor bar insertion hole 153 is formed at the center of the island-shaped region surrounded by the groove that becomes the engagement recess 151, and has a hole diameter slightly larger than the shaft diameter of the anchor bar 43 of the strut 40. Yes.

  As shown in FIG. 1 (a), the overhanging floor slab 20 for widening is connected to an existing overhanging floor slab 13 constituting the core structure 10 at the base end, and the distal end of the strut 40. Connected to the upper end. A connecting portion 21 to which the upper end portion of the strut 40 is connected protrudes from the lower surface of the distal end portion of the extended floor slab 20.

  As shown in FIG. 1B, the receiving member 30 is a member that serves as a tray for the strut 40, and is fixed to the pedestal portion 15 (that is, the lower portion of the main girder portion 11).

Although the material of the receiving member 30 is not particularly limited, in this embodiment, the compressive strength is 150 (N / mm ² ) or more, the split tensile strength is 5 (N / mm ² ) or more, and the bending strength is 15 It is made of ultra high strength fiber reinforced concrete that is (N / mm ² ) or more. If the receiving member 30 is made of ultra-high-strength fiber reinforced concrete, reinforcing members such as reinforcing bars are not required, so that the receiving member 30 can be made thinner, and in addition, there is no fear of corrosion. Subsequent maintenance and management becomes easier.

  The ultra-high-strength fiber reinforced concrete having the above-mentioned strength and characteristics is, for example, a high-performance premix powder containing cement, a pozzolanic reaction particle, and an aggregate having a maximum particle size of 2.5 (mm) or less. 1.0 volume of steel fibers having a shape with a diameter of 0.1 to 0.25 (mm) and a length of 10 to 20 (mm) are added to a cement-based matrix obtained by mixing a water reducing agent and water. % Or more can be obtained. The water cement ratio is desirably 0.24 or less. Here, the pozzolanic reaction particles are particles made of, for example, silica fume, fly ash, blast furnace slag, a compound selected from kaolin derivatives, precipitated silica, volcanic ash, silica sol, and the like.

  With reference to (a) and (b) of FIG. 2, the form of the receiving member 30 is demonstrated in detail. As shown in this figure, the receiving member 30 includes a main body portion 31 having a rectangular plate shape, and an engagement convex portion 32 formed on the back surface 31 b of the main body portion 31.

  The main body 31 is formed with a recess 311 having a truncated cone shape, anchor insertion holes 312, 312,..., And an anchor bar insertion hole 313. The recess 311 is recessed at the center of the surface 31 a of the main body 31. Although there is no restriction | limiting in particular in the depth of the hollow part 311, In this embodiment, it sets to the magnitude | size of about the half of the thickness of the main-body part 31. FIG. The anchor insertion hole 312 is a through-hole penetrating the main body portion 31 in the thickness direction, and is formed around the recessed portion 311 and the engaging convex portion 32 in the present embodiment. The hole diameter of the anchor insertion hole 312 is slightly larger than the shaft diameter of the anchor bolt 33. The anchor bar insertion hole 313 is a through hole that penetrates the main body portion 31 in the thickness direction, and is formed at the center of the recess 311 in this embodiment. The hole diameter of the anchor bar insertion hole 313 is slightly larger than the shaft diameter of the anchor bar 43 of the strut 40.

  The rear surface 31b of the main body 31 is subjected to roughening processing (rough surface processing). There is no particular limitation on the roughening processing method, but for example, shot blasting or the like can be used.

  The engaging convex part 32 is a part that enters the engaging concave part 151 of the pedestal part 15, and in the present embodiment, the engaging convex part 32 is composed of a ridge that has a frame shape. The engaging convex part 32 is located on the back side of the recessed part 311 and is formed integrally with the main body part 31. The width dimension of the ridge that becomes the engagement convex portion 32 is set to be equal to or less than the width dimension of the groove that constitutes the engagement recess 151, and the height dimension of the protrusion is equal to or less than the depth dimension of the engagement recess 151. Is set to The planar shape of the engaging convex portion 32 may be matched with the planar shape of the engaging concave portion 151. The engaging convex part 32 according to the present embodiment has a rectangular frame shape in accordance with the engaging concave part 151. In addition, in this embodiment, although the engagement convex part 32 is formed by the continuous protrusion with no cut | interruption, you may form the engagement convex part 32 by the protrusion formed intermittently.

  The receiving member 30 having such a form is in a fresh state in a mold frame (not shown) in which recesses 311, anchor insertion holes 312, anchor bar insertion holes 313 and engagement projections 32 are formed. It can be obtained simply by pouring the ultra-high-strength fiber reinforced concrete and performing appropriate curing.

  As shown in FIG. 1A, the strut 40 supports the extended floor slabs 13 and 20. In this embodiment, the strut 40 and the receiving member 30 are arranged at the front end portion of the widened extended floor slab 20. Between the two, and mainly supports the extended floor slab 20 for widening.

  As shown in FIGS. 2A and 2B, the strut 40 includes an elongated columnar portion 41, a protruding portion 42 protruding from the lower end surface of the columnar portion 41, and an end surface of the protruding portion 42. A protruding anchor bar 43 is provided.

  The columnar portion 41 is a rod-like structural element having a circular cross section (see FIG. 1A), and is formed of reinforced concrete. In addition, although illustration is abbreviate | omitted, in the upper end part of the columnar part 41, the fixed reinforcement embed | buried under the overhanging floor slab 20 is arranged.

  The projecting portion 42 is a portion that enters the recessed portion 311 of the receiving member 30, and has a truncated cone shape like the recessed portion 311. The protruding portion 42 is formed integrally with the columnar portion 41.

  The anchor bar 43 is provided to prevent the strut 40 from falling off the receiving member 30, and is inserted into the anchor bar insertion hole 313 of the receiving member 30 and the anchor bar insertion hole 153 of the pedestal portion 15. The The anchor bar 43 is fixed to the columnar portion 41.

  In the bridge upper structure A configured as described above, the shearing force acting on the strut 40 is generated by the shear key being formed by the engagement of the recess 311 of the receiving member 30 and the protrusion 42 of the strut 40. The shearing force that is transmitted to the receiving member 30 and further acts on the receiving member 30 by forming a shear key by meshing between the engaging concave portion 151 of the main girder portion 11 and the engaging convex portion 32 of the receiving member 30. Is transmitted to the main girder 11.

  Next, the construction method of the bridge superstructure A configured as described above will be described in detail with reference to FIGS. In addition, the construction method of the bridge superstructure A described below is also a method of widening an existing bridge superstructure (core structure 10 shown in FIG. 1A) installed between bridge piers (not shown).

  The bridge superstructure A is constructed by forming the engaging recess 151 on the outer surface of the lower part of the main girder part 11 (in this embodiment, the pedestal part 15) (see (b) of FIG. 3). The receiving member 30 is fixed to the pedestal portion 15 of the main girder portion 11 in a state where the engaging convex portion 32 formed on the back surface 31b enters the engaging concave portion 151 (see FIG. 3C), and then the strut 40 The lower end portion of the strut 40 is connected to the receiving member 30 (see FIG. 3D), and the upper end portion of the strut 40 is connected to the extended floor slab 20 (see FIG. 1A). In short, the construction method of the bridge superstructure A is characterized in that the receiving member 30 is retrofitted to the main girder 11 and the strut 40 is installed using the receiving member 30.

  If it demonstrates in detail, the construction method (the widening method of the core structure 10) of the bridge | bridging superstructure A is equipped with the recessed part formation process, the receiving member installation process, the strut installation process, and the connection process.

  In the recess forming step, the reinforcing bars arranged in the lower part of the main girder part 11 on the outer surface of the lower part of the main girder part 11 (the mounting surface 15a of the pedestal part 15 shown in FIG. 3A) are formed smoothly. This is a step of forming an engagement recess 151 having a depth equal to or less than the R cover thickness (see FIG. 3B). In order to form the engagement recess 151, the attachment surface 15a may be attached using an appropriate tool or the like. In the present embodiment in which the engagement recess 151 is formed by a groove, for example, a concrete cutter (not shown) is used. Incisions are formed to a predetermined depth at positions corresponding to the outer peripheral edge and the inner peripheral edge of the groove, and further, if necessary, to a predetermined depth along the center line of the groove at the intermediate portion between the outer peripheral edge and the inner peripheral edge of the groove. A cut may be formed and then the concrete left behind during the cut may be removed.

  The anchor insertion hole 152 and the anchor bar insertion hole 153 are drilled before or after the recess forming step. After the anchor insertion hole 152 is formed, the anchor bolt 33 is inserted into the anchor insertion hole 152 and fixed to the pedestal 15 using a mortar or an epoxy resin curing agent. In order to fix the anchor bolt 33 to the pedestal portion 15, for example, after inserting a capsule (not shown) containing a curing agent into the deep portion of the anchor insertion hole 152, the anchor bolt 33 is inserted into the anchor insertion hole 152. Then, the capsule may be crushed and the curing agent in the capsule may be cured in a gap around the anchor bolt 33.

  The receiving member installation step is a step of fixing the receiving member 30 to the main girder portion 11 in a state where the engaging convex portion 32 formed on the back surface of the receiving member 30 enters the engaging concave portion 151. In the receiving member installation process, the anchor bolt 33 is inserted into the anchor insertion holes 312 provided at the four corners of the receiving member 30, and the engaging convex portion 32 is inserted into the engaging concave portion 151, and then the surface 31 a side of the receiving member 30. The nut 34 is screwed into the anchor bolt 33 protruding to the side, and the back surface 31b of the receiving member 30 is brought into close contact with the mounting surface 15a of the pedestal portion 15 (see FIG. 3C). An epoxy resin adhesive is applied to at least one of the back surface 31b of the receiving member 30 and the mounting surface 15a of the pedestal portion 15, and the back surface 31b of the receiving member 30 is attached to the mounting surface 15a via the adhesive. Glue. In addition, it is also bonded to at least one of the engaging convex portion 32 and the engaging concave portion 151 so that shear transmission is possible between the engaging convex portion 32 of the receiving member 30 and the engaging concave portion 151 of the pedestal portion 15. An agent is applied in advance, and an adhesive is filled in the gap between the engaging convex portion 32 and the engaging concave portion 151.

  The strut installation step is a step of raising the strut 40 obliquely upward from the receiving member 30 while connecting the lower end portion of the strut 40 to the receiving member 30. In order to connect the strut 40 to the receiving member 30, the anchor bar 43 is inserted into the anchor bar insertion hole 153 of the pedestal portion 15 and the anchor bar insertion hole 313 of the receiving member 30, and the protrusion 42 is recessed in the receiving member 30. The anchor bar 43 may be fixed to the pedestal portion 15 with the lower end surface of the columnar portion 41 in close contact with the surface 31a of the receiving member 30 (see FIG. 3D). In order to fix the anchor bar 43 to the pedestal portion 15, a capsule (not shown) containing a curing agent is inserted into the deep portion of the anchor bar insertion hole 153, and then the anchor bar 43 is inserted into the anchor bar insertion hole 153. And the curing agent in the capsule may be cured in the gap around the anchor bar 43.

  Further, an epoxy resin adhesive is applied to at least one of the surface 31 a of the receiving member 30 and the lower end surface of the columnar portion 41 of the strut 40, and the lower end surface of the columnar portion 41 is applied to the surface 31 a of the receiving member 30. Glue. In addition, an adhesive is applied to at least one of the recess 311 and the protrusion 42 so that shear transmission is possible between the recess 311 of the receiving member 30 and the protrusion 42 of the strut 40. An adhesive is filled in the gap between the recess 311 and the protrusion 42. Instead of the adhesive, the above-described capsule curing agent may be wound around the gap between the recess 311 and the protrusion 42, or a grout material may be separately filled.

  In the connecting step, as shown in FIG. 1 (a), the base end portion of the extended floor slab 20 for widening is connected to the extended floor slab 13 of the core structure 10 which is an existing floor slab. This is a step of connecting the upper end portion of the strut 40 to the tip end portion (connecting portion 21) of the floor slab 20. In order to connect the overhanging floor slab 20 for widening to the existing floor slab (extended floor slab 13) and the strut 40, for example, a mold frame (not shown) for forming the overhanging floor slab 20 for widening is installed. At the same time, an upper end portion of the strut 40 and a fixing muscle (not shown) protruding from the upper end surface of the strut 40 are protruded into the mold, and an anchor (not shown) is provided on the side end surface of the overhanging slab 13 of the core structure 10. After placing a reinforcing material such as a reinforcing bar in the formwork, fresh concrete may be placed. In addition, what is necessary is just to connect with the existing floor slab (extended floor slab 13) or the strut 40 using the joint which is not shown in figure when comprising the extended floor slab 20 for widening by a precast segment.

  In the bridge upper structure A according to the present embodiment described above, the depth of the engagement concave portion 151 formed in the main girder portion 11 is equal to or less than the cover thickness of the reinforcing bar R (see FIG. 3B). The receiving member 30 is attached to the surface layer of the main beam part 11. In this case, unlike the case where the receiving member is buried deeper than the reinforcing bar R, it is not necessary to consider the contact with the receiving member 30 when the reinforcing bar R is arranged. The bar arrangement in the lower part of the is simplified. In addition, since the depth of the engaging recess 151 is set to be equal to or less than the cover thickness of the reinforcing bar R, a large-scale cutting work or the like with respect to the main girder part 11 becomes unnecessary, and further, there is no possibility of cutting the reinforcing bar R. Particularly in the present embodiment, since the frame-shaped groove is the engaging recess 151 (see FIG. 2A), the chipping work and the like become light.

  In the present embodiment, the back surface 31b of the receiving member 30 is roughened, and an adhesive is interposed between the back surface 31b of the receiving member 30 and the main girder portion 11. Therefore, the receiving member 30 Is firmly fixed to the main beam 11. In addition, rainwater or the like hardly enters between the back surface 31b of the receiving member 30 and the outer surface of the main girder portion 11, so that deterioration, frost damage, and the like hardly occur.

  Moreover, according to the construction method (widening method) of the bridge superstructure according to the present embodiment, even if the receiving member is not embedded in the main girder 11, the existing bridge superstructure (core structure) The body 10) can be widened. In addition, since the receiving member 30 is retrofitted, it is possible to set the mounting position, shape, etc. relatively freely, and therefore there is a demand for widening the existing bridge upper structure (core structure 10). Even after the core structure 10 is manufactured or installed, it can be easily handled.

(Modification)
In the above-described embodiment, the case where the engaging recess 151 of the main beam 11 is a frame-like groove (see FIG. 2A), but as shown in FIG. As long as it has a depth equal to or less than the cover thickness, the engaging recess 151 having a surface expansion may be used. Further, in the above-described embodiment, the engagement concave portion 151 into which only the engagement convex portion 32 enters (see (c) of FIG. 3) is formed, but in addition to the engagement convex portion 32, the main body portion 31 may enter. Even if it is the engagement recessed part 151 of the magnitude | size which can be performed, if it has the depth below the cover thickness of a reinforcing bar, it does not interfere (refer (a) of FIG. 5). In this case, an anchor insertion hole 152 is formed inside the engagement recess 151.

  In the above-described embodiment, the case where the engagement convex portion 32 of the receiving member 30 is a frame-shaped protrusion is illustrated, but when the engagement concave portion 151 of the main girder portion 11 has a planar spread. As shown in FIG. 4B, a plate-like protrusion having a planar expansion may be used as the engaging convex portion 32.

  In the above-described embodiment, the case where only the engaging convex portion 32 enters the engaging concave portion 151 and the back surface 31b of the receiving member 30 is brought into close contact with the outer surface (mounting surface 15a) of the main girder portion 11 is illustrated. When the planar shape of the recess 151 is such that the main body 31 of the receiving member 30 can enter, the main body 31 in addition to the engaging convex 32 as shown in FIG. The receiving member 30 may be fixed to the main girder portion 11 in a state where is inserted into the engaging recess 151. The engaging recess 151 may be filled with a filler 154 such as mortar.

  Even in the case as shown in FIG. 5A, since the depth of the engaging recess 151 is set to be equal to or less than the cover thickness of the reinforcing bar R, the receiving member 30 is attached to the surface layer of the main beam portion 11, As a result, compared to the case where the receiving member is embedded at a position deeper than the reinforcing bar R, the bar arrangement of the main girder 11 is simplified. In addition, since the depth of the engagement recess 151 formed in the main girder portion 11 is set to be equal to or less than the cover thickness of the reinforcing bar R, a large-scale chipping operation or the like on the main girder portion 11 becomes unnecessary.

  In the above-described embodiment, the case where the pedestal portion 15 is formed in advance under the main girder portion 11 and the mounting surface 15a is an inclined surface suitable for the inclination angle of the strut 40 is exemplified. When the mounting surface 15a is not suitable for the inclination angle of the strut 40, such as when the portion 15 is not formed, the back surface 31b of the receiving member 30 is placed on the front surface 31a as shown in FIG. Can be inclined with respect to.

  In the above-described embodiment, the case where the engaging recess 151 is formed by sandwiching the outer surface of the lower portion of the main beam portion 11 is illustrated (see (a) and (b) of FIG. 3). The engaging recess 151 may be formed when the main girder portion 11 is formed, for example, by forming a convex portion corresponding to the engaging recess 151 on the mold for forming the main girder.

  In the above-described embodiment, the case where the anchor insertion hole 312 is formed by drilling the outer surface of the lower part of the main girder part 11 and the anchor bolt 33 is fixed to the main girder part 11 via a curing agent is illustrated ( 3 (see (a) to (c) in FIG. 3), when the main girder 11 is formed, an insert nut made of steel or ceramic is embedded, and an anchor bolt 33 is screwed to the insert nut to anchor it. The bolt 33 may be fixed to the main beam portion 11.

  In the above-described embodiment, the case where the anchor bar insertion hole 313 is formed by drilling the outer surface of the lower part of the main girder part 11 is illustrated (see (a) and (b) of FIG. 3). 11 may be formed at the time of molding.

  In the above-described embodiment, the case where the recess portion 311 is provided on the surface 31a of the receiving member 30 and the protrusion portion 42 is provided on the lower end portion of the strut 40 is illustrated (see (a) and (b) in FIG. 2). A protrusion may be provided on the surface 31 a of the receiving member 30, and a recess may be provided on the lower end surface of the strut 40.

(A) is a front view which shows the bridge superstructure which concerns on embodiment of this invention, (b) is the figure which expanded the X part of (a). (A) is the disassembled perspective view of the site | part shown to (b) of FIG. 1, (b) is the perspective view which looked at the receiving member and strut shown to (a) from the back side. (A)-(d) is sectional drawing for demonstrating the construction method of the bridge | bridging superstructure which concerns on embodiment of this invention, and the widening method of a bridge | bridging superstructure. (A) is the disassembled perspective view for demonstrating the bridge upper structure which concerns on a modification, (b) is the perspective view which looked at the receiving member shown to (a) from the back surface side. (A) is sectional drawing for demonstrating the bridge superstructure which concerns on a modification, (b) is sectional drawing for demonstrating the bridge superstructure which concerns on another modification.

Explanation of symbols

A Bridge superstructure 10 Core structure (existing bridge superstructure)
11 Main girder part 13 Overhang floor slab
15 Base (lower part of main girder)
151 Groove 20 Overhanging slab for widening 30 Receiving member 32 Projection 40 Strut R Rebar

Claims (6)

The main girder,
An overhanging slab that protrudes laterally from the main girder,
A receiving member fixed to a lower portion of the main beam part;
A strut that rises obliquely upward from the receiving member, and a bridge upper structure in which the overhanging slab is supported by the strut,
An engagement convex portion is formed on the back surface of the receiving member,
An engaging recess having a depth equal to or less than the cover thickness of the reinforcing bar is formed on the outer surface of the lower portion of the main girder,
The bridge upper structure, wherein the receiving member is fixed to the main girder in a state where the engaging convex portion is inserted into the engaging concave portion. The engaging convex part is composed of a protrusion having a frame shape,
The bridge upper structure according to claim 1, wherein the engagement concave portion is a groove having a frame shape.   The bridge superstructure according to claim 1, wherein the receiving member is made of ultra high strength fiber reinforced concrete. The back surface of the receiving member has been subjected to roughening processing,
The bridge upper structure according to any one of claims 1 to 3, wherein a back surface of the receiving member is bonded to the main girder part via an adhesive. A method of constructing a bridge superstructure of a type in which an overhanging slab that projects sideways from a main girder part is supported by struts that rise obliquely upward from a receiving member fixed to the main girder part. ,
After forming an engagement recess having a depth equal to or less than the cover thickness of the reinforcing bar on the outer surface of the lower portion of the main girder, the engagement protrusion formed on the back surface of the receiving member is inserted into the engagement recess. The upper portion of the bridge, wherein the receiving member is fixed to the main girder portion in a state, and then the lower end portion of the strut is connected to the receiving member and the upper end portion of the strut is connected to the overhanging slab. How to build the structure. An overhanging slab for widening is provided on the side of the existing floor slab, and the strut that rises obliquely upward from a receiving member fixed to the main girder supporting the existing floor slab is supported. It is a method of widening the existing bridge superstructure,
A recess forming step for forming an engaging recess having a depth equal to or less than the cover thickness of the reinforcing bar on the outer surface of the lower portion of the main girder,
A receiving member installation step of fixing the receiving member to the main girder in a state where the engaging convex portion formed on the back surface of the receiving member is inserted into the engaging concave portion;
A strut installation step of raising the strut obliquely upward from the receiving member while connecting the lower end of the strut to the receiving member;
A connecting step of connecting a base end portion of the extended floor slab to the existing floor slab and connecting an upper end portion of the strut to a distal end portion of the extended floor slab. Widening method.

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